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# Matrix transformations watch

1. Q. The composite transformation M is defined by M = ABC where A,B and C are the transformations:

A; a reflection in the line through the origin at 30 degrees to the positive x-axis

B; a stretch in the y-direction of factor 2

C; a rotation of 45 degrees anticlockise about the origin

Find the matrix that represents M. Where have I messed up?

https://imgur.com/a/0eaJ9
2. (Original post by ckfeister)
Q. The composite transformation M is defined by M = ABC where A,B and C are the transformations:

A; a reflection in the line through the origin at 30 degrees to the positive x-axis

B; a stretch in the y-direction of factor 2

C; a rotation of 45 degrees anticlockise about the origin

Find the matrix that represents M. Where have I messed up?

https://imgur.com/a/0eaJ9
M is defined as ABC. Why have you worked out M' = CBA?
3. (Original post by ghostwalker)
M is defined as ABC. Why have you worked out M' = CBA?
It is the define of composite transformation, not the matrix M originally
4. (Original post by ghostwalker)
M is defined as ABC. Why have you worked out M' = CBA?
That's what I wondered at first, but the question isn't explicitly talking about matrices; just the order of transformations.
The reflection is done first, stretch second, then rotation. So for the matrix you start with matrix of (reflection) then onto (stretch)(reflection) then onto (rotation)(stretch)(reflection).

Although there's nothing wrong with his working, so they might've just meant the order of matrices ABC.

Not a fan of the way it is worded tbh.
5. (Original post by ckfeister)
It is the define of composite transformation, not the matrix M originally
Question doesn't say transformation order is A, then B, then C.
6. (Original post by RDKGames)
Not a fan of the way it is worded tbh.
Would be useful to see the original question, as is.
7. (Original post by RDKGames)
That's what I wondered at first, but the question isn't explicitly talking about matrices; just the order of transformations.
The reflection is done first, stretch second, then rotation. So for the matrix you start with matrix of (reflection) then onto (stretch)(reflection) then onto (rotation)(stretch)(reflection).

Although there's nothing wrong with his working, so they might've just meant the order of matrices ABC.

Not a fan of the way it is worded tbh.
Yes its all tricky wording and its annoying

(Original post by ghostwalker)
Question doesn't say transformation order is A, then B, then C.
I thought if it says " the composite transformation M is define as M = ABC ... find the matrix that represents M " would mean the original, but then it states find M as M= ABC. and that is correct.

I'd give a positive rating to you two but TSR is annoying with the new limit of 0 for 35 days then 2 the next, then none for 50 days.
8. (Original post by ckfeister)

I thought if it says " the composite transformation M is define as M = ABC ... find the matrix that represents M " would mean the original, but then it states find M as M= ABC. and that is correct.
Are you saying that as matrices M=ABC is correct then?

Or as you had, M'= CBA is correct?
9. (Original post by ghostwalker)
Are you saying that as matrices M=ABC is correct then?

Or as you had, M'= CBA is correct?
M = ABC, sort of logical if you think of it once you know but sometimes it states the composite is M = ABC, find the matrix M which means find CBA = M'

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